I am going for VBAC2 and have a back issue so although I have not had one yet I am in the same boat as your friend.
The first step is finding medical staff that will support her decision, I'm lucky enough to live in Newcastle where the director of Obstetrics is very supportive and encouraging toward VBAC's.
I was told I would not be induced synthetically ie my waters may be broken if needed but no drips or gel/pessaries will be given because the risk of scar rupture is higher with artificial induction techniques.
I am going to a VBAC class tomorrow at the hospital and I am happy to report back with info if you require it
Melissa